Wind

Texas curtailments of solar and wind could double by 2035 without grid upgrades: EIA

The state's main electric grid is adding renewable generation at a rapid clip while storage and transmission capacity expansion is not keeping up

The main electric grid in Texas will at least double curtailments of solar and wind by 2035 unless there is expansion of transmission and storage capacity to handle growing renewable share of total generation, according to a new US Energy Information Administration (EIA) study.

Ercot, which manages 90% of the state’s electric load, is the country’s number one wind power market and number two for solar and battery storage. Texas is experiencing strong economic and population growth as well as with energy consumption.

In 2022, Ercot curtailed 5% of total available wind generation and 9% of total available utility-scale solar.

“By 2035, however, we project wind curtailments in Ercot could increase to 13% of total available wind generation, and solar curtailments could reach 19%,” EIA said in the analysis, A Case Study of Transmission limits on Renewables Growth in Texas.

Curtailments are due to both inadequate transmission capacity and surplus generation during high availability periods of variable renewable generation.

“Our analysis shows that on days with more wind and solar generation and strong system electricity demand, limited transmission line capacity restricted wind and solar generation flows, and curtailments occurred,” said the report.

“These types of curtailments account for 36% of the projected curtailments in 2035, which could be reduced by upgrading the transmission system,” it added.

Still, EIA in its analysis found that 64% of curtailments occurred in 2035 when energy supply from solar and wind outpaced demand in Ercot.

“An increase in demand, such as through battery charging, could potentially reduce these types of curtailments,” said the report. EIA is the statistics arm of the US Department of Energy.

When solar and/or wind are curtailed from lower-cost resource areas, higher-cost resources are then dispatched. The cost of not having enough transmission capacity to move electricity from there to demand centres is represented by congestion cost.

In Ercot’s real-time market, congestion costs rose from $1.26bn in 2019 to $2.1bn in 2021. EIA projects they may rise to $2.8bn in 2035.

At the end of May, Ercot had 37.7GW of installed wind capacity and 3.5GW of storage capacity. On 1 July, there was 17.7GW of utility-scale solar in commercial operation.

In 2022, natural gas supplied 42.6% of energy consumed in Ercot, then wind, (24.9%); coal, (16.6%); nuclear, 9.7%. The remaining 6.2% was mainly solar with battery storage, biomass, fuel oil, landfill gas, petroleum coke, and imports of electricity providing the balance.

In 2035, EIA projects energy generation will grow about 7.3% to 462,500GWh in Ercot with natural gas providing 32%, wind 28%, solar 25%, nuclear 9%, coal 4%, and battery storage and other sources 2%.

If accurate, solar will largely replace coal and other fossil sources and significantly reduce natural gas’ market share.
EIA in its Annual Energy Outlook earlier this year projected that Ercot will add 52GW of solar and 4GW of wind capacity through 2035. That “reference case” reflected the agency’s current understanding of how the 2022 landmark federal climate law could impact capacity additions.

EIA also modeled a “high uptake” case whereby Ercot would add 63GW of solar capacity but only 2GW of wind. Its “low uptake” case was 37GW of solar and 2GW of wind.

The agency acknowledged several uncertainties are associated with these projections including adequacy of transmission capacity, changes in government policy, and pricing levels sufficient to incentivize additional new generating capacity.

(Copyright)
Published 19 July 2023, 22:58Updated 2 October 2023, 13:55
AmericasTexasERCOTEIA